Method of transferring and/or receiving data in communication system and apparatus thereof

ABSTRACT

The present invention relates to Walsh Code Allocation (WCA) field in the Packet Data Control Channel. One of the embodiments of the WCA field is use of the WCA field as Last Walsh Code Index (LWCI) field in the message format of the PDCCH. The LWCI field indicates the corresponding last code index or the corresponding number of Walsh codes in a Walsh Code Index (WCI) Table/List/Set. In alternative embodiments, the WCA indicates a general set of Walsh codes or a specific set of Walsh codes in the WCI table. The WCA fields may or may not be used with one of power ranking and sequential decoding, but is preferable used. The WCA field has various advantages including but not limited to efficient use of system resources.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of prior U.S. patentapplication Ser. No. 10/259,292 filed Sep. 30, 2002, which claimspriority under 35 U.S.C. §119 to Korean Application Nos. 60962/2001filed Sep. 29, 2001, 60963/2001 filed Sep. 29, 2001, 60964/2001 filedSep. 29, 2001, 63248/2001 filed Oct. 13, 2001, 63261/2001 filed Oct. 13,2001, 64014/2001 filed Oct. 17, 2001, and 68403/2001 filed Nov. 3, 2001,whose entire disclosures therein are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a communication system, and moreparticularly, to a method for transferring a packet data in a mobilecommunication system.

2. Background of the Related Art

Typically, radio communication systems for transferring packet data usephysical channels, such as, Packet Data Channel (hereinafter referred toas PDCH), Packet Data Control Channel (hereinafter referred to as PDCCH)and so forth.

The PDCH is a channel for use of transferring packet data that actuallyneeds to be transferred to a relevant terminal, mobile station or user(hereinafter being used interchangeably). Many users prefer the PDCHbased on the Time Division Multiplexing system (hereinafter referred toas TDM system). The PDCCH contains control information, enabling aterminal to receive the data being transferred through the PDCH withouterror.

When a base station transfers packet data using TDM system, or schedulesdata and later sending the data to each terminal in sequence, the packetdata, which is transmitted to every terminal, always uses all of theavailable resources, e.g., Walsh codes, in the PDCH. Even when only apart of the available resources needs to be used, all of the resourcesare still used for the packet data. As a result thereof, most of otherresources are wasted at the same time.

For example, data sent on PDCH need to be coded and decoded based onWalsh codes. Serial bits are converted to parallel, and the parallelbits are coded using the Walsh codes. In order to decode the data, theinformation regarding the Walsh codes is sent on the PDCCH.

In TDM system, there are plurality of time intervals 1, 2, 3, 4, 5, 6,etc, and only one of a plurality of terminals is allotted for each timeinterval where a PDCH and PDCCH are sent to the terminal during thisallotted time interval. For example, if there are users 1 and 3 and timeintervals 1 and 3, respectively, and if all 32-ary Walsh codes areavailable for use by terminal 1, all 32-ary Walsh codes are utilized inthe PDCH during time interval 1. However, if the available Walsh codesdecrease in time interval 3, all decreased Walsh codes are utilized forthe PDCH. Even before terminal 3 can use the changed/decreased Walshcodes in time interval 3, it needs to know this information. In order toachieve this, the BS broadcasts such information using a Walsh CodeSpace Identification Identifier (WSI) field in the PDCCH (without PDCH)with MAC_ID field information bit of (000000)2 before time interval 3 toall terminals within a cell.

A base station regularly or irregularly broadcasts WSI on the PDCCHwithout the PDCH to all terminals under its management. In the course ofthe broadcast, the base station uses every possible power for allterminals (even including terminals in the worst environment) to be ableto receive the information such that even the terminals in the worstenvironment can receive the WSI. Hence, the broadcasting consumes muchpower. Moreover, when the WSI change, the base station has to inform thechanges to all terminals every time. In those cases, the base stationcannot transmit PDCH, so the transmission efficiency of the entiresystem is consequently reduced.

The above references are incorporated by reference herein whereappropriate for appropriate teachings of additional or alternativedetails, features and/or technical background.

SUMMARY OF THE INVENTION

An object of the invention is to solve at least the above problemsand/or disadvantages and to provide at least the advantages describedhereinafter.

Another object of the invention is to provide a method for transferringpacket data to increase the resource usage efficiency.

Still another object of the invention is to provide a method fortransferring packet data for use of a system based on Code DivisionMultiplexing mode (CDM)/Time Division Multiplexing (TDM) mode.

The present invention can be achieved in a whole or parts by a methodcomprising allowing a plurality of users to receive data; and decodingthe data based on a table of code indices indicative of the channels,wherein a code index from the table indicate a prescribed channel fordecoding the data.

The present invention can be achieved in a whole or parts by a method ofproviding information regarding the channels, comprising sending a codeindex i from a plurality of code indices 0-N, wherein code index iindicates 0 to i channels

The present invention can be achieved in a whole or parts by a method ofdecoding data received through Pack Data Channel (PDCH) using a LastWalsh Code Index (LWCI) of a Packet Data Control Channel Messagetransmitted over the Packet Data Control Channel (PDCCH) with the PDCH,comprising: decoding the LWCI; and decoding the data using N number ofWalsh codes based on the LWCI.

The present invention can be achieved in a whole or parts by a messageformat of a Forward Packet Data Control Channel Message transmitted onat least one of F-PDCCH0 physical channel and F-PDCCH1 and havingMAC_ID, WALSH_MASK, EP_SIZE, ACID, SPID, AL_SN, EX_MSQ_TYPE ANDRESERVED, wherein the improvement comprises at least one of a first LastWalsh Code Index lwci0 of the F-PDCCH0 physical channel and a secondLast Walsh Code Index lwci1, and the lwci0 indicates that Walsh code setincludes 0^(th) through lwci0^(th) entries in a Walsh Code Index (WCI)table. Preferably, the WCI table may be pre-stored in a mobile stationand a base station, and respectively, the useable WCI table may bepredetermined by signaling channel with each other.

The present invention can be achieved in a whole or in parts by a methodof providing information regarding the channels, comprising sending acode index i from a plurality of code indices 0-N, wherein code index iindicates 0 to i channels.

The present invention can be achieved in a whole or in parts by a methodcomprising: allowing a plurality of users to receive data; decoding thedata based on a table of code indices indicative of the channels,wherein a code index from the table indicate a prescribed channel fordecoding the data.

The present invention can be achieved in a whole or in parts by a methodfor decoding data in a communication network, comprising: determining aprescribed value from a prescribed number of bits of a received field,wherein the prescribed value corresponds to at least one value in atable of first values; and determining a set of second values based onthe prescribed value to decode the data, wherein there is a prescribedrelationship between the first values and the second values.

The present invention can be achieved in a whole or parts by a method ofallocating codes for corresponding data channels from a prescribednumber of codes comprising: assigning code indices to the prescribednumber of codes, such that there is a one-to-one correspondence betweeneach code index and each code; transmitting a control message over thecontrol channel, the control message having a plurality of fields,wherein one of the fields contains prescribed number of information bitsbased on at least one code index; and transmitting the data over thePDCH, wherein control message and data are sent concurrently.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objects and advantages of the invention may be realizedand attained as particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

FIG. 1 illustrates a format of the Packet Data Control Channel (PDCCH)Message in accordance with a preferred embodiment of the presentinvention;

FIG. 2 is a diagram illustrating packet data transmission using TimeDivision Multiplexing (TDM) system in accordance with a preferredembodiment of the present invention;

FIG. 3 is a diagram illustrating packet data transmission using CDM/TDMsystem in accordance with a preferred embodiment of the presentinvention;

FIG. 4 illustrates WCI Table/List/Set in accordance with a preferredembodiment of the present invention;

FIG. 5 illustrates WCI Table where Walsh Code Allocation (WCA) field isused as Last Walsh Code Index (LWCI) field in accordance with apreferred embodiment of the present invention;

FIG. 6A illustrates masking of the Walsh codes in accordance with apreferred embodiment of the present invention;

FIG. 6B illustrates another embodiment of the WCA field in accordancewith a preferred embodiment of the present invention;

FIG. 7A illustrates another embodiment of the WCA field in accordancewith a preferred embodiment of the present invention;

FIG. 7B illustrates another embodiment of the WCA field in accordancewith a preferred embodiment of the present invention;

FIG. 8 illustrates another embodiment of the WCA field in accordancewith a preferred embodiment of the present invention;

FIG. 9 illustrates another embodiment of the WCA field in accordancewith a preferred embodiment of the present invention;

FIG. 10 illustrates another embodiment of the WCA field in accordancewith a preferred embodiment of the present invention;

FIG. 11 illustrates another embodiment of the WCA field in accordancewith a preferred embodiment of the present invention;

FIGS. 12A and 12B illustrate a PDCH transmission chain structure inaccordance with a preferred embodiment of the present invention; and

FIG. 13 illustrates a general PDCCH transmission chain structure inaccordance with a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates the format of the Packet Data Control Channel (PDCCH)Message in accordance with the preferred embodiment (describedhereinafter), over the PDCCH, e.g., forward PDCCH (F-PDCCH). TheCWSI/LWSI field of the message format preferably prevents wasted powerconsumption caused by broadcasting, and eliminates such broadcast. Evenif broadcasting is used, the additional field of CWSI/LWSI reduces theinefficiencies of a prescribed system. This message format can be usedin both a TDM system, i.e., one PDCH physical channel and one PDCCHphysical channel within a prescribed time interval and uses theavailable Walsh codes, and a Code Division Multiplex (CDM) system, i.e.,a plurality of PDCH(i) physical channels and a plurality of PDCCH(i)physical channels, where i is an integer number that is greater than orequal to 0, within a prescribed period of time and the plurality ofusers are assigned to a plurality of physical channels by allocation ofthe Walsh codes within the Walsh code space.

It is noted that the Walsh code, PDCH, and PDCCH are not necessarilylimited to their definitions. Rather, they generally represent codes andchannels having such prescribed functions. Further, N_(max) _(—) _(PDCH)is the maximum number of PDCHs or PDCCHs available for a relevant systemor sector, where N_(max) _(—) _(PDCH)>0. N_(real) _(—) _(PDCH) is thenumber of PDCHs or PDCCHs that are currently being used for a relevantsystem or sector at a certain point, where 0<N_(real) _(—)_(PDCH)≦N_(max) _(—) _(PDCH).

For example, in a TDM based packet data transfer method illustrated inFIG. 2, i.e., N_(max) _(—) _(PDCH)=1 and N_(real) _(—) _(PDCH)=1, a basestation schedules the data to transfer, and sends the data to eachterminal in order. In doing so, the base station uses the currentlyavailable Walsh codes for PDCH.

In FIG. 2, a time length of a transmission unit on PDCH and PDCCH couldbe fixed or varied. Further, the time length of PDCH and PDCCH does nothave to be the same. The user k means packet data or control informationfor a user k. The transmission time and length of PDCH and PDCCH for theuser k are determined in conforming to a prescribed rule. Further, thetime gap between PDCH transmission and PDCCH transmission for each usermay exists or may not exist at all, depending on the system environment.The same applies to a dual mode system.

In a dual mode system, such as a CDM/TDM system, involves a base stationscheduling the data to be transferred to each user and sending the datafollowing the TDM and CDM method. Although this system is referred to asa dual mode system, it can be appreciated by one of ordinary skill inthe art that a CDM system can be viewed as a single mode system, since aCDM system inherently includes a TDM mode, i.e., where only one userwithin a prescribed the length.

For example, a single PDCH with a corresponding PDCCH could betransferred at a prescribed length of the transmission unit (intervald), or several PDCH(i) with corresponding PDCCH(i) could be transferredtogether (interval a, b, c and e, etc). The PDCCH(i) is an individualPDCCH physical channel having its own control information. In a TDMmode, i.e., a single PDCH is transferred of interval d, the Walsh codesneed not be divided. But if a plurality of PDCH(i) are transferred, theWalsh codes are divided or allocated between the physical channels.

FIG. 3 illustrates a case in which a maximum 4 PDCHs could exist in theCDM/TDM system. The empty space shown in FIG. 3 indicates when PDCH orPDCCH is not occupied or used. For example, during the interval a, fourPDCH(i) are transferred with four corresponding PDCCH(i). Thereafter,during interval b, three PDCH(i) are transferred with threecorresponding PDCCH(i). During interval c, three PDCH(i) are transferredwith three corresponding PDCCH(i) and during interval d, one PDCH(i) istransferred with a corresponding PDCCH(i). During interval e, fourPDCH(i) are transferred with four corresponding PDCCH(i).

As discussed above, the message format of PDCCH includes a plurality offields, e.g., 9 fields, and a prescribed number of bits are used foreach fields to form the control information bits. Based on the binaryvalue of the bits, each field provides a prescribed control function forthe operation of the user to use the data/information received on thePDCH. The description of the fields illustrated in FIG. 1 is as follows:

-   -   (1.) MAC_ID: The MAC identifier filed is a prescribed number of        binary bit that is used for identifying a user. Preferably, the        prescribed number of binary bits is 8 for the MAC_ID field.        Except for ‘00000000’to ‘00111111’, the MAC_ID field indicates        which terminal the PDCCH information is being transferred. The        base station preferably sets this field to the MAC identifier        assigned to the user that is to decode a PDCH subpacket        transmission, e.g., forward PDCH (F-PDCH), concurrent with the        transmission of this message on the PDCH. If the MAC_ID is set        to ‘00000000’, the base station preferably includes the        WALSH_MASK field of a prescribed number of bits, e.g., 0 or 13,        and omits the remaining fields. Otherwise, the base station        preferably omits the WALSH_MASK field and includes the remaining        fields.    -   (2.) WALSH_MASK: The Walsh Space Mask Bitmap field is preferably        set by the base station to indicate that the mobile station, is        to omit certain entries in the packet data channel Walsh set        when decoding the PDCH, e.g., F-PDCH. The base station        preferably sets each bit in this filed to ‘0’ or ‘1’ to indicate        that the mobile station is to include (‘0’) or omit (‘1’) the        corresponding indices in the Walsh index table (WCI—to be        described hereinafter).    -   (3.) EP_SIZE: The Encoder packet size field comprises a        prescribed number of bits, e.g., 0 or 3 bits, that indicates the        number of data information bits being transferred on the PDCH.        For example, if this message field contains an extended message,        the base station preferably sets this field to the encoded value        for the encoder packet size (other than ‘111’) for the PDCH        subpacket transmission concurrent with transmission of this        message on the PDCH. If EP_SIZE is not set to ‘111’, the base        station preferably includes ACID, SPID, AI_SN and LWCI/CSWI (to        be described hereinafter). If the EP_SIZE is set to ‘111’, the        base station preferably includes the fields, EXT_MSG_TYPE and        RESERVED, and otherwise, the base station omits these two        fields.    -   (4.) ACID, SPID and AI_SN: The ARQ Channel Identifier field        (ACID), the Subpacket Identifier field (SPDI) and ARQ Identifier        Sequence Number field (AI_SN), each comprising a prescribed        number of bits (preferably, 0 or 3, 0 or 2, 0 or 2, and 0 or 1,        respectively), and each is preferably set by the base station        for the PDCH subpacket transmission concurrent with the        transmission of this message on the PDCH. The ACID and SPID are        used to inform a terminal whether the information on the PDCH,        which corresponds to PDCCH, is retransmitted or not. For        instance, the ACID informs a mobile station (assuming that it        can transfer a number of retransmitted channels) which channel        is being retransmitted among other retransmitted channels, and        which subpacket in the retransmitted channel (especially for the        encoded symbols from an information stream that is being        repeated and split to designated subpackets) is being        transferred.    -   (5.) EXT_MSG_TYPE: The Extended Message Type Identifier field        has a prescribed bit length (preferably, 0 or 2) and is        preferably set by the base station to be ‘00 ’ or ‘01’. The base        station may set this field to ‘00’ to indicate that the mobile        station to exit a prescribed mode, e.g., PDCH Control Hold Mode.        The base station may set this field to ‘01’ to indicate that the        mobile station is to terminate the current switching        transmission pattern prior to the maximum number of switching        frames.    -   (6.) RESERVED: The Reserved Bits field has a prescribed bit        length (preferably 0 or 8 bits) and is preferably set by the        base station to be ‘00000000’.    -   (7.) LWCI/CWSI: The Last Walsh Code Index (LWCI) field, which        can be also called a CDM Walsh Space Identification (CWSI)        field, is based on Walsh codes within a Walsh code space and/or        a code index. The label “x_i” indicates that the number of bits        x may vary depending upon the corresponding PDCCH(i) physical        channel and the code indices may or may not be based on        priority. However, for the embodiment using the LWCI field, “x_i        ” equals 0 or 5 bits for all PDCCH(i) physical channels and 5        bits is sufficient for each PDCCH for allocating all the        possible Walsh code allocation patterns in the preferred        embodiment.

As can be appreciated, the number of bits for this field can differdepending on the number of all possible code allocation pattern and thetype of codes, e.g., Walsh codes, being used. Further, the field forLWCI/CSWI serve the substantially the same function/way/result ofallocating Walsh codes for use by a corresponding PDCCH(i), and thisfield can be generally called a Walsh Code Allocation (WCA) field.Depending upon the embodiments, the WCA field can be used to indicatethe number of codes used or a general/specific set of Walsh codebelonging to the WCI table based on the code indices.

In the preferred embodiment, the Walsh code is a common name of codeshaving orthogonality to each other and is generally used fortransmission over the physical channel. As can be appreciated, differenttypes of codes can be used depending on the system. The Walsh code spaceis a set of currently available Walsh codes when a base stationtransfers packet data, and the Walsh code space can vary depending upontime. Walsh_Max indicates a maximum number of Walsh codes that the Walshcode space can accommodate and Walsh (all) is a parameter indicating allWalsh codes that are usable for PDCH on the Walsh code space. Based onthe Walsh codes within the Walsh code space, a code index from 0 to aprescribed number (num), where num>0 are assigned with a correspondingWalsh code within the Walsh code space. The assignment of the codeindices to the Walsh codes in the Walsh code space can also be basedupon priority.

FIG. 4 illustrates a 32-ary Walsh Code Indices (WCI) Table (or Set orList) where Walsh_Max=28 within the Walsh code space with a code index(e.g., num=0 to 27) assigned to each Walsh code within the Walsh codespace. FIG. 4, illustrates a 32-ary Walsh Code, but as can beappreciated by one of ordinary skill in the art, this can be different,e.g., 64-ary Walsh Code, based on the system requirements. Further,Walsh_Max is illustrated herein as exemplary, and not limited to a valueof 28. Preferably, the WCI table may be pre-stored in a mobile stationand base station, and the usable WCI table may be predetermined bysignal channeling between each other.

In composing the WCI table, the code index is based on priorities ofevery Walsh code in the Walsh code space. For example, if there are atotal of 28 Walsh codes (Wal_Max=28) available for composing the Walshcode space, every Walsh code corresponds to a code index. However, sincethe WCI table of the preferred embodiment lists the Walsh codes from thehighest priority to the lowest, a lower code index corresponds to ahigher priority. However, when the Walsh codes in the Walsh code spaceneed to be allocated to the PDCH/PDCCH, the allocation may be based onpriority (priority allocation) where the lowest code indexed Walsh codesare used before the higher code indexed Walsh codes, or priorities donot matter (non-priority allocation), e.g., a Walsh code with the lowestpriority may be used first before a Walsh code with the highest prioritycode index.

In one of the preferred embodiments using the WCA field, especially forthe embodiment using the LWCI field, power ranking is preferably used todetermine which terminal is assigned to which PDCCH physical channel.Unless specifically indicated in the foregoing embodiments, powerranking may or may not be used. In other words, the modulation symbolstransmitted on PDCCH (i) should be transmitted using at least as muchenergy as the modulation symbols transmitted on PDCCH(i+1) which istransmitted simultaneously with PDCCH(i). The power ranking generallyassures that all terminals properly receive the information sent on thePacket Data Control Channel (PDCCH). In the preferred embodiment, powerranking is based on the required transmission power of the PDCCH of eachscheduled user, i.e., when N PDCCH(i)/PDCH(i) are used at some timeinterval, user requiring the most power is assigned PDCCH(0) and userrequiring the least power is assigned PDCCH(N−1). Alternatively, a userwith the worst environment is assigned to PDCCH(0) and a user with thebest environment is assigned to PDCCH(N−1).

For example, the terminal furthest away from base station, i.e., theterminal using the largest amount of power, is assigned to PDCH(0) andPDCCH(0), the terminal second furthest away from the base station isassigned PDCH(1) and PDCCH(1), the terminal third furthest away from thebase station is assigned PDCH(2) and PDCCH(2), etc, such that powerranking of the PDCCH(i) physical channels is as followsPDCCH(0)≧PDCCH(1)≧ . . . PDCCH(i)≧ . . . ≧PDCCH(N−2)≧PDCCH (N−1),assuming that there are N number of terminals within a prescribed timeinterval.

For example if terminal 1 requires 3 mW and terminal 3 requires 7 mW,e.g., terminal 3 is further away from the base station than terminal 1or terminal 3 is located in an environment which is worse than theenvironment of terminal 1, then PDCH(0) and PDCCH(0) is assigned orallocated to terminal 3 and PDCH(1) and PDCCH(1) is assigned orallocated to terminal 1.

Although in this example, power ranking was based on distance, thisillustration is intending to be illustrative of power ranking, and thepresent invention is not to be limited based on this example sincedistance of the terminals is one of the ways for using the power rankingand other factors can be used for power ranking with or without distanceconsideration.

In 3GPP2 C.S0003-C v1.0, the 3GPP2 group has decided to use two physicaldata channels, PDCH(0) and PDCH(1), with two corresponding physicalcontrol channels, PDCCH(0) and PDCCH(1) and power ranking is used toassign terminals to the physical channels. In other words, themodulation symbols transmitted on the PDCCH(0) should be transmittedusing at least as much energy as the modulation symbols transmitted onthe PDCCH(1) that is being transmitted simultaneously.

General Setup in Accordance with a Preferred Embodiment.

A base station uses an appropriate channel to inform N_(max) _(—)_(PDCH) to terminals under its management. N_(max) _(—) _(PDCH) could bea maximum PDCCH(i) a relevant system or a sector can simultaneously useor the number of PDCH(i), and N_(max) _(—) _(PDCH) could be either fixedor variable. The base station decides N_(real) _(—) _(PDCH)(≦N_(max)_(—) _(PDCH)) according to the scheduling result. If N_(real) _(—)_(PDCH) is 1, it involves the TDM system, and if N_(real) _(—) _(PDCH)is greater than 1, it involves the CDM system. Thereafter, the basestation can use as many as PDCH/PDCCH based on the N_(max) _(—) _(PDCH),e.g., PDCH(0)/PDCCH(0), PDCH(1)/PDCCH(1), . . . , and PDCH (N_(max) _(—)_(PDCH−)1)/PDCCH(N_(max) _(—) _(PDCH)−1) as control channels.

A terminal preferably needs to find out which Walsh code is being usedto transmit PDCCH, and the terminal may obtain a Walsh Code list (WCL)from the base station, in which the WCL includes the Walsh codes PDCCHuses, and the base station provides the WCL. The code indices wcl(0),wcl(1), . . . , and wcl(N_(max) _(—) _(PDCH)−1) preferably have aone-to-one relationship with the PDCCH(0), PDCCH(1), . . . , andPDCCH(N_(max) _(—) _(PDCH)−1), i.e., PDCCH(i) is transmitted by usingwcl(i), based upon a predetermined rules between the base station andthe terminals under its management.

Walsh Code list (WCL) is used to differentiate the different PDCCH(i)channels, whereas, WCA(i) is a field included in each PDCCH(i) toindicate a number of corresponding Walsh codes or a general/specific setof Walsh codes which is used to decode the data received via PDCH(i).Similar to WCI, the WCL is preferably stored in a mobile station and abase station, and the usable WCL may be obtained by channel signalingbetween each other.

General Decoding in Accordance with the Preferred Embodiment

When a terminal interprets each WCA(i) received through controlchannels, the interpretation of these field can be done independently inthe preferred embodiment(s). For example, if the WCA field is indicativeof a specific set (rather than a general set or a number ofcorresponding Walsh codes) of Walsh codes based on the code indices, theintended user matches the MAC_ID and obtains the WCA(i) withoutreference to other WCA(j) (i≠j).

In alternative preferred embodiment(s), the WCA(i) field may beindicative of the code index to form a set of Walsh codes or the WCA(i)field is indicative of a general set number of Walsh codes based on thecode indices in the WCI table, the interpretation is preferablydependent upon other WCAs, where in order to interpret WCA(i), theterminal preferably refers to another WCA(j)(i≠j) based upon apredetermined condition for more accurate interpretation of its ownWCA(i) value.

As discussed above, WCL is preferably used to differentiate eachPDCCH(i) from one another. In this instance, the base station transmitsPDCH(i) to a corresponding terminal in accordance with the PDCCH(i)information contain the MAC_ID of the corresponding terminal, and theterminal matches its MAC_ID and the MAC_ID of PDCCH(i). For example, theterminal sequentially decodes PDCCH(0), PDCCH(1), . . . , PDCCH(N_(max)_(—) _(PDCH)−1) using wcl(0), wcl(1), . . . , wcl(N_(max) _(—)_(PDCH)−1) until it finds its own MAC identifiers. Alternatively, theterminal can decode channels in a reverse order of PDCCH(N_(max) _(—)_(PDCH)−1), PDCCH(N_(max) _(—) _(PDCH)−2), . . . , PDCCH(0) usingwcl(N_(max) _(—) _(PDCH)−1), wcl(N_(max) _(—) _(PDCH)−2), . . . , wcl(0)until it finds its own MAC_ID.

The predetermined condition for the WCA(i) may be based on WCA(i−1)being found. In this case, a terminal or a user who is assigned toreceive the WCA(i) of PDCCH(i) should be able to receive thecorresponding WCA values that are being transferred on PDCCH(0),PDCCH(1), . . . , PDCCH(i−1) or at least a terminal assigned to receivethe WCA(i) of PDCCH(i) should be able to receive the WCA(i−1) that isbeing transferred on PDCCH(i−1). Unless explicitly indicated, thissequential decoding may or may not be used in the forgoing embodiments.

First Preferred Embodiment of WCA Field

The following will be a discussion related to the use of the WCI Tableusing the Walsh codes indices corresponding to the column index “000” inFIG. 4 as WCA field. Further, this explanation will be focus on twophysical channels, (1) PDCH(0) and PDCCH(0) and (2) PDCH(1) andPDCCH(1), which is exemplary of the disclosure in 3GPP2 C.S0003-C v1.0,but is not intended to limit the scope of the claimed invention and thedisclosure herein.

As discussed above, the LWCI field is based upon the use of the codeindices based on priority allocation, e.g., the PDCCH(0) physicalchannel is allocated a first set of Walsh codes corresponding to thelower code indices and the PDCCH(1) physical channel is thereafterallocated to second set of Walsh codes corresponding to the higher codeindices after the first set of lower code indices have been assigned. Inother words, the available Walsh codes in the Walsh code space isdivided into a plurality of sets of Walsh codes, where the lower codeindices are allocated or assigned to a lower numbered PDCCH. As can beappreciated, this priority can be reversed, where higher code indicesare first allocated to a lower number PDCCH in an alternative embodiment(non-priority allocation).

Power ranking is also preferably used with the LWCI field, i.e., theterminal requiring the most power is assigned to PDCCH(0), and theterminal requiring the least power is assigned PDCCH(1). As can beappreciated, power ranking is preferable especially when there are morethan two terminals. As can be further appreciated, power ranking may ormay not be needed when two physical channels for two correspondingterminals are used, but is preferable.

For example, FIG. 5 illustrates the WCI Table, where there are 28 Walshcodes (Walsh_Max=28) in the Walsh code space, and each Walsh code isassigned to a corresponding code index. As discussed above, theavailable Walsh codes can change even though there are 28 Walsh codes inthe Wash codes space. For example, based on power ranking, terminal 1 isassigned to PDCCH(0) and terminal 3 is assigned to PDCCH(1). If the LWCIfield (lwci0) of PDCCH(0) equals 3 (00011)₂ and the LWCI field (lwci1)of PDCCH(1) equals 9 (01001)₂, the Walsh codes are divided into twosets, where Walsh codes corresponding to indices 0-3 would be allocatedto PDCCH(0) and Walsh codes corresponding to indices 4-9 would beallocated to PDCCH(1). Hence, the PDCH(0) for terminal 1 is transmittedon Walsh codes 31, 15, 23, and 7 while the PDCH(1) for terminal 3 istransmitted on Walsh codes 27, 11, 19, 3, 30 and 14.

In other words, the terminal assigned to PDCCH(0) transmission of thePDCH(0) occurs on Walsh codes with index 0 to index i in the WCI table,where i=the binary bits indicated in the LWCI field (lwci0) of thePDCCH(0). The terminal assigned to PDCCH(1) transmission of the PDCH(1)occurs on Walsh codes with index (i+1) to the j-th Walsh code, wherej=the binary bits indicated in the LWCI field (lwci1) of the PDCCH(1).

As shown in FIG. 5, the present invention does not use all the Walshcodes in the WCI Table, and Walsh codes from code index 10 to code index27 can be used for other purposes. Further, the WCI Table is dividedinto two sets and allocated for PDCCH(0) and PDCCH(1) transmission ofPDCH(0) and PDCCH(1), respectively. Moreover, this allocation of the WCITable can be readily applicable to situations where more than twophysical channel assignments are required. With such CDM scheduling, thebase station is no longer required to broadcast within an entire cellthe available codes.

Similar to CDM scheduling, the LWCI field (lwci0) of PDCCH(0) is used toindicate the available Walsh code space in TDM scheduling. Only PDCCH(0)is used and PDCCH(1) is suspended. Further, if there are more than twophysical channels, PDCCH(1) to PDCCH(N_(max) _(—) _(PDCH)−1) aresuspended. Likewise, not all available Walsh codes need to be used, andbroadcasting is not required in this preferred embodiment.

In terms of the mobile station or terminal, a sequential decoding of thePDCCH is performed by all mobile station. Starting from PDCCH(0), themobile station keeps on decoding the PDCCH until its correspondingMAC_ID is found. Once detecting the corresponding MAC_ID on thePDCCH(i), the mobile station assigned to PDCCH(i) collects the LWCIfields (lwci(i−1)) of PDCCH(i−1) and the LWCI field (lwci(i)) ofPDCCH(i).

For example, when PDCCH(0) has been assigned to terminal 1 fortransmission of PDCH(0), terminal 1 decodes the PDCCH(0) to determinelwci0. Since the code indices are based on priority allocation, terminal1 can determine that PDCH(0) has been transmitted based on Walsh codesfrom index 0 to index lwci0 of the WCI table. However, for terminal 3assigned to PDCCH(1) for transmission of PDCH(1), terminal 3 needs tocollect the lwci0 in order to determine the Walsh codes from indexlwci0+1 to index lwci1. Although terminal 3 can readily collect thelwci1 based on the MAC_ID of the PDCCH(1), terminal 3 still needs toobtain lwci0 from PDCCH(0). Due to power ranking, terminal 3 canascertain that PDCCH(0) is transmitted with a higher power than itselfor at least a equal power. Based on power, terminal 3 can obtain thelwci0 from PDCCH(0) to decode the PDCH(1) using the Walsh codescorresponding to index lwci0+1 to index lwci1.

In certain instances, the Walsh codes in the WCI table may be masked,and the terminal needs to receive the information regarding the maskedWalsh codes to properly determine lwci(i), e.g., lwci0 and lwci1. FIG.6A illustrates the masking of Walsh codes corresponding to indices 1-3(lightly shaded with italic text and underling). It is noted that Walshcodes from indices 13-27 (darkly shaded with bold text and underling)are used for other purposes.

In such a situation, the base station notifies all the terminals bysending on PDCCH(0) with a MAC_ID field of ‘00000000’ and the WALSH_MASKfield indicating which corresponding indices in the WCI table need to beomitted or deleted during a first prescribed time interval. Further,lwci0 is equal to −1 (negative 1). Thereafter, during the PDCCH(1)transmission of PDCH(1) within the first prescribed time interval, thecorresponding terminal deletes the Walsh codes corresponding to theindices indicated to be omitted from PDCCH(0). Based upon such deletion,the decoding of PDCH(1) is based upon the WCI table illustrated in FIG.6A. For example, if lwci1 on PDCCH(1) is equal to 12 and since −1(lwci0)+1 equals 0, the PDCH(1) is decoded using Walsh codes 31, 27, 11,19, 3, 30, 14, 22, 6 and 26 (Walsh codes corresponding to indices 0-12).Hence, the WALSH_MASK is applied to walsh codes determined by lwci0 andlwci1.

During the second prescribed time interval after the first prescribedtime interval, a terminal is assigned to the PDCCH(0) transmission ofthe PDCH(0) includes a message format having a lwci0 field of 4 andanother terminal is assigned to the PDCCH(1) transmission of the PDCH(1)includes a message format having a lwci1 field of 12. When the terminalassigned to PDCCH(0) obtains the lwci0 of 4, the masked Walsh codes aredeleted as shown in FIG. 6A, and Walsh codes used for decoding PDCH(0)are 31 and 27. After the terminal assigned to PDCCH(1) obtains both thelwci0+1 and lwci1, the masked Walsh codes are deleted, as shown in FIG.6A, and the Walsh codes used for decoding PDCH(1) are 11, 19, 3, 30, 14,22, 6 and 26.

Based on the above description, the following applies when LWCI is usedas a field for the PDCCH. The base station preferably sets this field tothe last Walsh code index for the PDCH subpacket transmission concurrentwith the transmission of this message on the PDCCH. If this message isbeing transmitted on the PDCCH(0) physical channel, the base stationpreferably sets this field to indicate that the Walsh code set includesthe 0th through LWCIth entries in the WCI table. Otherwise, if thismessage is being transmitted on the PDCCH(1) physical channel, the basestation preferably sets this field to indicate that the Walsh code setincludes the (lwci0+1)th through LWCIth entries in the WCI table. If theMAC_ID in the PDCCH(0) message transmitted at the same time as thismessage is greater than or equal to ‘01000000’, then lwci is the lastWalsh code index in the PDCCH(0) message. If the MAC_ID in the PDCCH(0)message is less than ‘01000000’, lwci0 is −1.

Second Preferred Embodiment of WCA Field

FIG. 6B is a diagram illustrating one of WCA interpretation method using5-bit WCA in accordance with another embodiment of the presentinvention. Referring to FIG. 6B, which illustrates the Walsh codescorresponding to column “001” of FIG. 4, the Walsh codes disposedbetween a position corresponding to WCA(m−1) value and WCA(m) value arethe ones used for the transmission of PDCH(m). As can be appreciated byone of ordinary skill in the art, there is no substantive differencebetween the first preferred embodiment and this second preferredembodiment other than the location of the code index within the WCItable. Hence, the code index number and location within the WCI tablecan be arbitrary decided. Further, N or M both refer to Walsh code usersfor transferring the PDCH, and are just arbitrary labels. Moreover, thelabel (i) for PDCH(i) or PDCCH(i), WCA(i) and WCL(i), where i=0 to aprescribed number, are also arbitrary, e.g., i can be 1 to a prescribednumber.

When there are a plurality of physical channels, N_(max) _(—) _(PDCH)greater than 1, i of FIG. 1 has a range from 0, 1, . . . , to (N_(max)_(—) _(PDCH)−1). The WCA(i) of PDCCH(i) is the information about thosecodes that are used for transferring PDCH(i). Usually, the number ofbits x_i of the WCA field does not have to be a fixed number of bits,but can vary depending upon the whether this field indicates the numberof Walsh codes based on the code index, and/or this field indicates aspecific set of the codes belong to the Walsh code space of the WCItable. In this preferred embodiment, every message format of thePDCCH(i) has an identical configuration, i.e., the number of informationcontrol bits x_i is 5 for every PDCCH(i).

The WCA(0) on the PDCCH(0) indicates that the same number of Walsh codeswith the WCA(0) value is used from the WCI table, starting from the codeindex indicative of higher priority Walsh codes. If i is greater thanzero, the CWSI on the PDCCH(i) means a specific set of the codes takenfrom the Walsh code space of the Code priority table, following aspecific rule. Specifically, the WCA(i) (i>0), of the PDCCH(i) indicatesthat the data is being transferred on the PDCH(i) using the Walsh codesfrom a relevant set based on the code index.

In addition, when i is greater than zero, the WCA(i) on the PDCCH(i)indicates that the WCA(i) value corresponds to the code index in the WCItable such that the number of Walsh codes indicated by the code index inthe WCI table (except for the Walsh codes used by PDCH(0), PDCH(1),PDCH(2), . . . , and PDCH(i−1)) is used based on priority allocation fortransferring PDCH(i). The base station performs scheduling to make thetransmission power of PDCCH(i) equal to or stronger than that ofPDCCH(i+1) based on the assumption that the terminal for transmission ofPDCCH(i) is located in a better or similar communication environmentthan the terminal for transmission of PDCCH(i+1), i.e., power ranking.Further, when a terminal interprets a WCA(i) value of PDCCH(i), itpreferably uses the WCA(j) information of other PDCCH(j) other thanPDCCH(i), i.e., sequential decoding.

For example, suppose that the CDM/TDM system is used, and N_(max) _(—)_(PDCH) is 2, and broadcasting is not used. Hence, two of each PDCH(0),PDCCH(0), PDCH(1), and PDCCH(1) are used. If the WCA(0) field of thePDCCH(0) corresponds to the index code 4 of the WCI table, the samenumber (1-4) of Walsh codes, e.g., 31 (code index=1), 15 (code index=2),23 (code index=3) and 7 (code index=4) in FIG. 6B, corresponding to theindex code 4 are used for the transmission of PDCH(0).

Further, if the WCA(1) field of PDCCH(1) corresponds to the code index10 of the WCI table, the WCA(1) value indicates that the correspondingnumber of Walsh codes, except for the Walsh codes used by the PDCH(0),are taken from the WCI table for the transmission of PDCH(1), startingfrom the higher priority code indexed Walsh codes to the lower prioritycode indexed Walsh codes, e.g., 27 (code index=5), 11 (code index 6), 19(code index=7), 3 (code index=8), 29 (code index=9) and 13 (codeindex=10) of FIG. 6B.

As can be appreciated for all the embodiments, the composition of theWCI table allows many flexibilities. In this embodiment and the previousembodiment, the last code index has been used, but the code index canalso be used as beginning Walsh Code index (BWCI). For example, ifWCA(0)=4, PDCCH(0) will indicate Walsh codes 31, 15, 23 and ifWCA(1)=10, PDCCH(1) will indicate Walsh codes 7, 27, 11, 19, 3, and 29.Based on the disclosure of the embodiments, the implementation will beapparent to one of ordinary skill in the art.

Third Preferred Embodiment of WCA Field

FIG. 7A illustrates another preferred embodiment of the presentinvention, where the code indices for WCA are used as start code numbers(SCN) and end code numbers (ECN). As shown in FIG. 7, which is one ofthe exemplary methods of using the SCN/ECN, the message format of FIG. 1will include SCN and/or ECN (SCN/ECN) field for PDCCH(i) having either 0or x_i number of bits rather than LWCI/CWSI field. The SCN/ECN indicatesa specific set of Walsh codes in the WCI Table based on the codeindices.

For example, if there are N number of users and Walsh codescorresponding to code indices 0 to 16 from the WCI table are available,where the other Walsh codes are used for other purposes, the SCN/ECNfield for the 1st user (terminal or mobile station) of PDCCH(i) fortransmission of PDCH(i), where i=0 to N−1 and i between different usersare not the same, will include a SCN(0) of 0 and a ECN(0) of 3, theSCN/ECN field for the 2nd user of PDCCH(i) will include a SCN(1) of 4(ENC(0)+1) and a ECN(1) of 9, . . . , and the SCN/ECN field for the Nthuser of PDCCH(i) will include a SCN(N−1) of 13 (ECN(N−2)+1) and ECN(N−1)of 16 within a prescribed time interval for CDM scheduling.

In other words, the PDCH(i) for the 1st user is transmitted on Walshcodes 31, 15, 23, and 7, the PDCH(i) for the 2nd user is transmitted onWalsh codes 27, 11, 19, 3, 29 and 13, . . . , and the PDCH(i) for theNth user is transmitted on Walsh codes 9, 30, 14 and 22. In terms ofdecoding, the 1st user searches for the corresponding MAC_ID field toobtain or collect the SCN and the ECN information bits, the 2nd usersearches for the corresponding MAC_ID field to obtain or collect the SCNand the ECN information bits, . . . , and the Nth user searches for thecorresponding MAC_ID field to obtain or collect the SCN and the ECNinformation bits in control message of the PDCCH(i).

In this embodiment, the priority, power ranking and/or sequentialdecoding may or may not be used due to the flexibility of this Walshcode allocation. For example, if none of the above is used, the SCN andECN fields would comprise, for example, 10 bits, where 5 bits is wouldbe representative of the SCN information bits and the other 5 bits wouldbe representative of the ECN information bits. In such a case, thedifferent users search for the corresponding MAC_ID field incorresponding PDCCH transmission of the PDCH, and use the Walsh codescorresponding to the SCN and the ECN in the WCI table.

If priority of the code indices is used, the PDCCH(0) will be allocatedwith the lowest code indices or the highest code indices, depending uponthe order of priority. In such an instance, there is no need for theSCN(0) for the PDCCH(0) since this will be equal to 0 or the highestcode index in the WCI table. Hence, the SCN/ECN field of PDCCH(0) maybe, for example, 5 bits representative of the ECN information bitscorresponding to a set of lower code indices within the WCI tablewhereas the SCN/ECN fields of the remaining PDCCH(i), where i=0 to N−1,will include both SCN(i) and ECN(i) information bits.

If both priority of the code indices and power ranking is use, the sameas above applies to the PDCCH(0) physical channel. However, the SCN/ECNfield of the last PDCCH(N−1) physical channel does not need to containone of SCN(N−1) and ECN(N−1) information bits. For example, if theSCN/ECN field includes, for example, 5 information bits representativeof SCN(N−1) of the code indices, the Nth user can readily utilize theWalsh codes corresponding to the set of code indices starting fromSCN(N−1) to the last code index within the WCI table. Alternative, ifthe SCN/ECN field includes, for example, 5 information bitsrepresentative of ECN(N−1) of the code indices, the Nth user can readilyutilize the Walsh codes corresponding to the set of code indicesstarting from the ECN(N−1) to the ECN(n−2)+1.

In another modification which uses priority, power ranking andsequential decoding, SCN/ECN field become the same as the LWCI field. Inthis instance, the SCN/ECN would preferable contain ECN informationbits, which would be the same as LWCI field. Hence, the descriptionabove regarding the LWCI field is readily applicable to this preferredembodiment. Further, the discussion regarding masking is also readilyapplicable to this preferred embodiment whether or not priority orpriority allocation, power ranking and/or sequential decoding isapplied.

For TDM scheduling or mode, the PDCCH(0) is preferably used to provideECN(0) of 5 bits, and the other physical channels PDCCH(1) to PDCCH(N−1)are suspending similar to the embodiment of LWCI.

This embodiment has various advantages. For example, in both CDM and TDMscheduling or mode, broadcasting is not required since the PDCCH istransmitted with the corresponding MAC_ID information. Further, Walshcode allocation (CDM) and available Walsh space indication (TDM) can beperformed in a common manner. Also, the Walsh code allocation can bedone in a fully flexible manner such that there is flexibility in systemoperation.

Fourth Preferred Embodiment of the WCA Field

FIG. 7B illustrates another embodiment of WCA interpretation inaccordance with the present invention. This embodiment is similar to theembodiment of FIG. 7A. In other words, there is no substantivedifference between the two embodiments other than the numbering of thecode indices and what location or point in the WCI table the codeindices corresponds to the Walsh codes. As can be appreciated, the indexnumbering and location on the WCI table to reference the Walsh codes canbe arbitrary decided. For transmission of PDCH(m) for m>=0, the WCA(m)field of the PDCCH(m) will contain a value which would indicate thatWalsh codes disposed between a starting position calculated by Equation1 and an ending position calculated by Equation 2 are used.$\begin{matrix}{\sum\limits_{i = 0}^{m - 1}\quad{{WCA}(i)}} & \left\lbrack {{Equation}\quad 1} \right\rbrack \\{\sum\limits_{i = 0}^{m}\quad{{WCA}(i)}} & \left\lbrack {{Equation}\quad 2} \right\rbrack\end{matrix}$

For example, the Walsh codes used for transferring PDCH(m) correspondsto Walsh codes from the code index starting point 14[=WCA(0)+WCA(1)+ . .. +WCA(m−1)=14] and the code index ending point 19[=WCA(0)+WCA(1)+ . . .+WCA(m)]. In this preferred embodiment, the code index starting point ofPDCH(0) is zero based on priority allocation. That is, the Walsh codesused for transferring PDCH(0) are the ones between the cod indexstarting point 0 and the code index ending point 4[=WCA(0)].

The WCA(m) can be interpreted by a terminal independently and onceWCA(m) of PDCCH(m) including a terminal's MAC identifier is interpreted,any arbitrary terminal can get the information about the Walsh codesthat are used by PDCH(m) where its packet data is being transferred.

The independent interpretation on WCA(m) by a terminal is largelydivided into two cases. In the first case, all WCA(m) values have thesame meaning. In the second case, one of the WCA value among all otherWCA values has a different meaning.

In the first case, a plurality of control channels PDCCH (i) includesinformation regarding the Walsh codes that are positioned in the WCItable based on the first and the last code index. When PDCH(m) istransferred by using codes placed between a certain code index(Start_Walsh_Code; hereinafter referred to as SWC) in the WCI table andanother specific code index (End_Walsh_Code; hereinafter referred to asEWC) in the Code priority table, the WCA(m) value comprises the value ofthe SWC and EWC.

For example, suppose that the WCA information bit on PDCCH(i) is 10 bits(x_i=10), then WCA(1)=(00100 01010)₂, as illustrated in FIG. 7B. Thestarting point Walsh code is based on a SWC index whose position on theWCI table is 00100₂=4₁₀, and the ending Walsh code is based on a EWCindex whose position on the WCI table is 01010₂=10₁₀. In this firstcase, every WCA(m) field of PDCCH(m) can use the same message format,e.g., x_i=10.

In the second case, at least one WCA(m) is based on a single code indexnumber indicative of the number of Walsh codes used for the datatransmission channel in accordance with the priority allocation, and theother WCA(m) include both the SWC index and the EWC index according tothe priority allocation. In such a case, PDCCH(i), except for PDCCH(0),can use the same configuration with each other such that x_(—)0=5, andx_i=10(i>0). In general, if i is larger than 0, x_i is twice x_(—)0. Inthis example based on the illustration of FIG. 7B, the x_i equals 5 forWCA(0) and WCA(0)=(00100)=code index 4, which indicates that the numberof Walsh codes equals the corresponding Walsh codes based on the codeindex 4 on the WCI table in accordance with priority allocation, i.e.,Walsh codes 31, 15, 23 and 7.

However, for WCA(m), where m>0, the WCA(m) field includes both the SWCindex and the EWC index in the WCI table. In this example based on theillustration of FIG. 7B, the number of bits of WCA(m)=x_i=10, where m>0such that WCA(1)=(00100 01010), where SWC=4 and EWC=10, . . . ,WCA(m)=(01110 10011), where SWC=14 and EWC=19, . . . , andWCA(M−1)=(10111 11010), where SWC=23 and EWC=26.

Fifth Embodiment of the WCA Field

Walsh(i) is a set of Walsh codes the PDCH(i) uses at a particular timeof transmission. It is composed of the components of the Walsh codespace. Although the Walsh code space does not change, the Walsh codesincluded in the Walsh(i) changes based on time. In other words, aprevious Walsh(i) and a current Walsh(i) have different components andthe total number of their components. The Walsh code unit for theWalsh(i) is x, and the number of components of each Walsh(i) is amultiple of x., i.e., 1x, 2x, 3x and so forth. Here, the number ofcomponents of Walsh(i) is independent of the number of Walsh(all).

For example, if Walsh_max is 28, the Walsh code usage unit is 3, and thebit number of the WCA field is 6 based on WCA field indicates the numberof Walsh codes (vs. WCA field containing the information about the set,in which case the number of bits of the WCA field can be as many asnecessary.), the 11 points (e.g., P_(—)0, P_(—)1, . . . , P_(—)10, asshown in FIG. 8) can be designated in the WCI table and a total of 55sets can be created from this 11-point set although a total of ‘2⁶=64’sets can be used based on the number of bits of the WCA field. Hence,there is a one to one (1:1) correspondence of the 11-point set WCA valuebut the remaining WCA values, ‘64 −55=9’, may be used for differentpurposes

Sixth Embodiment of WCA Field

FIG. 9 illustrates another preferred embodiment, where the WCA is usedas Walsh code index set values (WCISV), in which case the message formatof FIG. 1 will include CISV field for PDCCH(i) having either 0 or x_inumber of bits rather than LWCI/CWSI field. In this preferredembodiment, the code indices divided into sets based on the valueindicated in the WCISV field of the PDCCH(i). The WCISV field isindicative of a general set of Walsh codes of the WCI table based on thecode indices. Preferably, priority, power ranking and sequentialdecoding is used.

In the example shown in FIG. 9, the WCISV(0) field of PDCCH(0) wouldequal 4 for the 1st user, which would indicate that the Walsh codescorresponding to the 1st four code indices of the WCI table ispreferably used to for transmission of the PDCH(0). Similarly, theWCISV(1) field would equal 6 for the 2nd user, which would indicate thatthe Walsh codes corresponding to code indices from WCISV(0)+1 toWCISV(0)+WCISV(1) is preferably used for transmission of the PDCH(1).The WCISV(n) field would equal 4 for the nth user, which would indicatethat Walsh codes corresponding to code indices from WCISV(0)+WCISV(1)+ .. . +WCISV(n−1) to WCISV(0)+WCISV(1)+ . . . +WCISV(n−1)+WCISV(n) ispreferably used for transmission of the PDCH(n). Due to sequentialdecoding, the user can collect the WCISV fields from PDCCH(0) toPDCCH(n). The number of information bits for this field is preferably be5, but can be different depending upon the number of possible variationsof the Walsh code allocation.

In TDM mode, the PDCCH(0) physical channel can be used to transmit theavailable Walsh codes with the WCISV(0) field. Again, no broadcasting isrequired and the various advantages described above can be readilyapplicable to this embodiment.

Seventh Embodiment of the WCA Field

When a terminal interprets WCA(i) with reference to other WCA(j) thatare receives through a control channel, if a PDCCH(i) satisfies aspecific condition, the WCA(i) bit number, x_i, of the PDCCH(i) can beset to zero. In other words, given that the WCA is not broadcasted, andif the transmission power of a previously transmitted control channelamong a plurality of control channels is the same or greater than thetransmission power of a control channel that is to be transmitted, thenumber of bits of WCA of the control channel that is to be transmittedis 0. Hence, a terminal, which received WCA of 0 bits in the controlchannel implicitly interpreted such 0 bits of the WCA as indicative ofusing Walsh codes except the ones presently used for other controlchannels among the Walsh codes used for the plural control channelspreviously.

FIG. 10 illustrates control channels in terms of time when the number ofbits of WCA(M,t2) is set to 0 bit in accordance with this preferredembodiment of the present invention. In this embodiment, it is thatassumes PDCCH(i) transferred during a prescribed time interval t isPDCCH(i, t), and WCA on the PDCCH(i, t) is WCA(i, t), and the PDCHcorresponding to the PDCCH(i, t) is PDCH(i, t). Further, the controlchannels that a base station transfers during a specific time intervalt1 are PDCCH(1, t1), PDCCH(2, t1), . . . , PDCCH(L, t1), and the controlchannels during the next time interval t2 are PDCCH(1, t2), PDCCH(2,t2), . . . , PDCCH(M, t2), where L and M are arbitrary natural numbers.

If the following conditions are satisfied, the number of bits forWCA(M,t2) of PDCCH(M, t2) could be 0. The transmission power of PDCCH(L,t1) is equal or greater than the transmission power of PDCCH(1, t2). Ina such case, the Walsh codes for transferring PDCH(M,t2) are theremaining codes except for the Walsh codes that are used fortransferring PDCCH(1, t2), PDCCH(2, t2), . . . , and PDCCH(M−1, t2)}among the Walsh codes used for transferring PDCCH(1, t1), PDCCH(2, t1),. . . , and PDCCH(L, t1).

Eighth Embodiment of the WCA Field

In the above-described embodiments, there is a possibility there aremore than one PDCCH(i) having the same MAC identifier among a theplurality of PDCCHs being simultaneously transferred. In other words,among {PDCCH(0), PDCCH(1), . . . , PDCCH(N_(real) _(—) _(PDCH)−1)}, theMAC identifier for PDCCH(i) and for PDCCH(j)(i≠j) could be identicalwith each other.

In this instance, the terminal may collectively regard part or all ofthe PDCHs corresponding to the PDCCHs having the same MAC identifier asone PDCH, and the terminal may undertake the reception procedure thereof(e.g., performing decoding, or error correction code check) and performssignal processing thereon. The terminal determines, with reference tothe other information bits besides the MAC_ID, whether it shouldcollectively regard certain PDCHs among the plurality of PDCHscorresponding to PDCCHs with the same MAC identifier as one PDCH/PDCCH.

If the MAC_ID of two PDCCH are the same (two is intended to beexemplary), but EP_SIZE, ACID, AI_SN, and SPID are different, theterminal regards the two PDCHs and two corresponding PDCCHs asdifferent, and the terminal undertakes the reception procedure for eachPDCH separately. However, if the MAC_ID, EP_SIZE, ACID, AI_SN, and SPIDare the same, the terminal collectively regards the two PDCHs and PDCCHsas one PDCH and PDCCH, and the terminal initiates the receptionprocedure for one PDCH/PDCCH. Further, the Walsh codes that are used fortransferring PDCH at this time are the ones that are used by therelevant PDCHs for relevant PDCCHs.

For example, if PDCCH(2) and PDCCH(5) have the same MAC_ID, EP_SIZE,ACID, AI_SN, and SPID, the PDCH(2) and the PDCH(5) being transferred areactually as one PDCH. Hence, if the WCA(2) and WCA(5) fields of PDCCH(2)and PDCCH(5) indicates Walsh codes 31, 15, 23 and Walsh codes 22, 6, 26,10, and 18, respectively, based on a code index indicative of a numberof Walsh codes in the WCI table, or based on a general set of Walshcodes corresponding to code index or based on a specific set of Walshcodes corresponding to the code index, the terminal can readilydetermine that Walsh codes 31, 15, 23, 22, 6, 26, 10, 18 is to be usedfor decoding.

Ninth Embodiment of the WCA Field

In addition to the above embodiments illustrating the use of theadditional field which is broadly labeled as the WCA field, a CodeDivision Multiple Indicator field (hereinafter referred to as CDMI) maybe further added to the information bits of PDCCH(i) in order toincrease the overall system efficiency, as illustrated in FIG. 11( ).The CDMI allows the terminals to know the number of control channelsthat are currently being transferred through the CDM system. FIG. 11also illustrates the number of information bits in the message format ofPDCCH(i) (excluding EXT_MSG_TYPE and RESERVED). The CDMI is used toinform the terminal as to whether there are additional PDCCH to bereceived, and if so, the terminal can estimate the number of controlchannels that are being transferred through the CDM system.

According to a predetermined rule between the terminal and the basestation, the CDMI(i) will indicate to the terminal that it is suppose toreceive another PDCCH(k). For example, if CDMI(i)=(0)₂, this willindicate to the terminal that it will not receive PDCCH(k) since thereis no PDCCH(k), and if CDMI(i)=(1)₂, this will indicate to the terminalthat it should attempt to receive PDCCH(k), if necessary, since there isa PDCCH(k). As can be appreciated, the value of 0 or 1 or vice versa canbe use to indicate whether there is another control channel, andfurther, other values of CDMI may be used. To implement this embodiment,the terminal preferably includes an additional device for detectingdifferent bit number of the CDMI. One example of the additional devicesis generating error detection bits in accordance with the bit number ofy_i when PDCCH is generated.

Tenth Embodiment of the WCA Field

For the purpose of improving the applicability of Walsh codes, the Walshcodes that are reserved for the transmission of PDCCH(i) (i.e., codes inthe Walsh Code Space) can be used for the transmission of PDCHs if acorresponding PDCCH(i) is not currently using the Walsh codes. In suchcase, the base station preferably informs the terminals which PDCHs areusing the Walsh codes in the WCI table. In such a case, the CDMI of theprevious embodiment can be used for such a task.

The base station allows the terminals to know which Walsh codes in theWCI table are being used for which PDCH based on the code indices. Theterminals, discovering in which PDCCH(i) a specific value of CDMI isfound, concludes which Walsh codes in WCI table are used for which PDCH.In complying to the predetermined rule(s) between the base station andthe terminals, a terminal is supposed to receive PDCCH(i) and thereafterPDCCH(k). If the value of the CDMI(i) equals 0, there is no PDCCH(k).

For example, let assume that N_(max) _(—) _(PDCH) is 4, and WCL=wcl(0),wcl(1), wcl(2), and wcl(3). When CDMI(i) value on a certain PDCCH(i) is0, the Walsh codes for use of the transmission of PDCH(i) correspondingto PDCCH(i) includes the Walsh codes that are allocated for transferringPDCH(i) in the WCI table, and the Walsh codes that are not yet used byPDCCH(0), PDCCH(1), . . . , PDCCH(i) in the WCI table. For instance,suppose that PDCCH(1) indicates a PDCCH whose CDMI value is 0. Then,among wcl(2) and wcl(3), the codes, which satisfy the predeterminedrequirements between the terminal and the base station, are usedadditionally for transferring PDCH(1).

Eleventh Embodiment of the WCA Field

As previously described in some of the embodiment, the WCA can be usedfor the TDM system or TDM scheduling. However, all the previousembodiments are readily applicable to TDM system or TDM scheduling. InTDM system, N_(max) _(—) _(PDCH) is equal to 1, and hence, TDM systemuses only one PDCH(i) and one PDCCH(i), and the other PDCHs and PDCCHsare suspended. In such an instance, the WCA can be used as WSI, butwithout the need to broadcast regularly or intermittently. Further, theWCA serving as the WSI can allocate the resources such that not allavailable Walsh codes are used for transmission of the PDCH(i) andPDCCH(i).

In this instance, the 5-bit WCA, 2-bit ACID, and the 3-bit EP_SIZE arepreferably used. Further, the value of the WCA represents the code indexon the WCI table, and represent the number of codes from the highestpriority code indexed Walsh code to the lower priority code index Walshcode of the WCI table, e.g., LWCI. For example, if the value of WCA is‘00011₂(3₁₀)’, 3 Walsh codes from code index 0 to code index 3 of FIG. 5are used for transmission of the PDCH and thereafter, the WCA can beused to decode the data on the PDCH by the terminal. Further, since thePDCCH(i) includes the MAC_ID, broadcasting is not needed and such thatthe WCA need not be transferred to all terminals, but only to aparticular relevant terminal requiring the WCA.

Twelfth Embodiment of the WCA Field

In the above 11 embodiments, WCA was not broadcasted to all theterminals, but was transferred only to specific terminals. However, theunique feature of the WCA allows flexibility such that WCA may be usedvia broadcasting using a prescribed control channel. This controlchannel may be one of the existing control channels or a newbroadcasting channel labeled as Walsh Code Allocation Channel.

For example, when N_(max) _(—) _(PDCH) is 2, two PDCH(i) and twoPDCCH(i) are used, wherein i=0 and 1. Assuming that the PDCCH(0) is usedfor broadcasting, the information bits on the PDCCH(0) are set up in aparticular way, e.g., MAC_ID equals ‘00000000’, and SPID is set up as‘11’ and the 2-bit ACID is added with the x_(—)0 bits, e.g., 5 bits, ofthe WCA. This can be broadcasted to all the terminals to notify theavailable Walsh codes. The 5 bit WCA can indicate the number of Walshcodes in the WCI table, e.g., LWCI, a general set of Walsh codes in theWCI table or a specific set of Walsh codes in the WCI table.Alternatively, the PDCCH(1) physical channel can be used for suchbroadcasting.

Transmission Chain for Packet Data Channel Structure

The Packet Data Channel preferably transmits a prescribed number ofinformation bits, e.g., 386, 770, 1538, 2306, 3074, or 3842 bits.Sixteen packet frame quality indicator bits and six turbo encoder tailallowance bits are added to the information bits to form encoderpackets. The encoder packets are encoded with a rate-1/5 turbo encoder,interleaved, and scrambled. Thereafter, symbols from the scrambledsequence are selected for transmission as a subpacket. The selectedsymbols may not include all of the scrambled output symbols or they mayinclude all of the scrambled output symbols with some symbols repeatedone or more times. The selected subpacket symbols are modulated intoQPSK, 8-PSK, or 16-QAM symbols and demultiplexed into one to 28 32-chipWalsh channels used for that Forward Packet Data Channel. Each of theseWalsh channels is spread with a different 32-chip Walsh function. Then,the spread symbols on the Walsh channels are summed to obtain a singlesequence of I/Q-symbols.

FIGS. 12A and 12B illustrate such a transmission chain for the PDCH. Theprescribed number of information bits of the PDCH is inputted to a CRCgenerator 10 to add 16 frame quality indicator bits and thereafter to atail allowance generator 11 to add 6 turbo encoder tail allowance bits.A Cyclic Redundancy Code (CRC) is a class of linear error detectingcodes, which generate parity check bits by finding the remainder of apolynomial division. The encoder tail bits a fixed sequence of bitsadded to the end of a block of data to reset the turbo encoder to aknown state.

A turbo encoder 12 discards the turbo encoder tail allowance bits andadds turbo encoder output tail bits such that the number of bits out ofthe rate-1/5 turbo encoder is five times the number of bits in anencoder packet. The encoder packets are turbo encoded with a code rateof 1/5.

During encoding, an encoder output tail sequence is added, and the turboencoder generates Nturbo/R encoded data output symbols followed by 6/Rtail output symbols, where R is the code rate of 1/2, 1/3, 1/4, or 1/5,where Nturbo is the total number of information bits and frame qualityindicator bits. The turbo encoder 12 employs two systematic, recursive,convolutional encoders connected in parallel, with an interleaver, theturbo interleaver, preceding the second recursive convolutional encoder.The two recursive convolutional codes are called the constituent codesof the turbo code. The outputs of the constituent encoders are puncturedand repeated to achieve the (Nturbo+6)/R output symbols.

The turbo encoder output sequence is interleaved by a channelinterleaver 13. The interleaving comprises symbol separation, subblockinterleaving, and symbol grouping of the turbo encoder output sequence.Every interleaver output symbol are exclusive-OR'd with thecorresponding bit of the scrambling sequence generated by a scrambler 13based on a public long code mask or a private long code mask to yield ascrambled output bit.

Subpacket symbols are selected from the scrambler output sequence by aselector 15. Encoder packets are transmitted as one or more subpackets.Initially, the first subpacket is transmitted. Then, subsequentsubpackets are transmitted if requested by the mobile station. Thesymbols in a subpacket are formed by selecting specific sequences ofsymbols from the interleaved and scrambled turbo encoder outputsequence. The resulting subpacket sequence is a binary sequence ofsymbols for a modulator 16.

The symbols from the subpacket symbol selection process are modulated.The modulator 16 maps the symbols from the subpacket symbol selectionprocess into a sequence of QPSK, 8-PSK, or 16-QAM modulation symbols.The type of modulation depends on the encoder packet size, number ofWalsh channels, and number of slots.

The modulated symbols are demultiplexed into Walsh channels, each Walshchannel is Walsh spread, and the spread symbols from the Walsh channelsare summed. A demultiplexer 17 demultiplexes the in-phase stream at theoutput of QPSK/8-PSK/16-QAM modulator into N parallel streams, I1, I2, .. . , IN, where N is the total number of 32-chip Walsh codes that areindicated in WCI_SET (i.e., WCI table). Similarly, the quadrature streamat the output of the QPSK/8-PSK/16-QAM modulator are demultiplexed intoN parallel streams, Q1, Q2, . . . , QN. For each k=1, 2, . . . , N, thedemultiplexed streams with labels Ik and Qk are assigned to the in-phaseand quadrature phases, respectively, of the kth Walsh code that appearsin the WCI_SET. Following the Walsh channel spreading, the spreadsubpacket modulation symbols from the Walsh channels are summed by asummer 18 to form a single sequence of (I, Q) symbols.

After performing a orthogonal spreading and channel gain, each codechannel is spread in quadrature by a spreader. The spreading sequence ispreferably a quadrature sequence of a prescribed length, e.g., 215(i.e., 32768 PN chips in length). This sequence is called the pilot PNsequence. Following the spreading operation, the I and Q impulses areapplied to the inputs of the I and Q baseband filters 20 a and 20 b.Thereafter, the outputs of the filters 20 a and 20 b are mixed, summedand transmitted over the PDCH.

On the terminal side, the decoding is substantially the reverse of thisencoding process.

Transmission Chain for Packet Data Control Channel Structure

FIG. 13 illustrates a general configuration of PDCCH transmission chainin accordance with one preferred embodiment of the present invention.The input sequence of PDCCH includes 2-bit ARQ channel identifier, 3-bitencoder packet size, 1-bit AI_SN, x_i-bit WCI, and 2-bit subpacketidentifier with or without the 8-bit MAC,

An error detection code like CRC (cyclic redundancy check) code in anerror detection code adding block 101 to the input sequence. This addedbit is provided with tail bits for sending a final state of the encoderfrom a tail bit adding blocks 102 trellis termination. The bits withtail bit are encoded to convolutional code at the encoder 103.

The encoded bits are repeated to a prescribed repetition factor at thesymbol repetitive block 104. Such repeated bits goes through puncturingprocess at the symbol puncturing block 105. Those puncturing processedbits are interleaved at the block interleaver 106, and are modulated atthe modulator 107, in conforming to QPSK method. The modulated signalsare divided into I channels and Q channels, by using part of the Walshcodes indicated by WCL.

For a given base station, the I and Q pilot PN sequences for the ForwardPacket Data Control Channel preferably use the same pilot PN sequenceoffset as for the Forward Pilot Channel. The modulation symbolstransmitted on the first Forward Packet Data Control Channel(PDCCH_ID=‘0’) should preferably be transmitted using at least as muchenergy as the modulation symbols transmitted on the second ForwardPacket Data Control Channel (PDCCH_ID=‘1’) that is being transmittedsimultaneously, N_(max) _(—) _(PDCH) is 2.

The tail bit generator generates the last eight bits of each ForwardPacket Data Control Channel frame are called the Encoder Tail Bits.Preferably, each of the eight bits is set to ‘0’. The encoderconvolutionally encodes as the PDCCH frame. Preferably, the encoder isinitialized to the all-zero state at the end of each frame. The encodedPDCCH frame undergoes code symbol repetition and the code symbolsresulting from the symbol repetition are punctured. The modulationsymbols on the PDCCH are then interleaved, and the interleaver block isalign with the PDCCH frame. The modulation signal is provided to thesignal point mapping block (e.g., modulator) for transmission

The foregoing embodiments and advantages are merely exemplary and arenot to be construed as limiting the present invention. The presentteaching can be readily applied to other types of apparatuses. Thedescription of the present invention is intended to be illustrative, andnot to limit the scope of the claims. Many alternatives, modifications,and variations will be apparent to those skilled in the art. In theclaims, means-plus-function clauses are intended to cover the structuresdescribed herein as performing the recited function and not onlystructural equivalents but also equivalent structures.

1. A method of transmitting packet data in a communication system,comprising: transmitting a control message over a packet data controlchannel, the control message having a LWCI field for indicating that acode set used in a packet data channel includes the 0_(th) through theLWCI_(th) codes on a code list; and transmitting packet data over thepacket data channel using the 0_(th) through the LWCI_(th) codes on thecode list.
 2. The method of claim 1, wherein the code allocationinformation is an index (LWCI) of a last code included in the portion ofthe code list.
 3. The method of claim 2, wherein the portion of the codelist includes the 0_(th) through the LWCI_(th) code on the code list. 4.The method of claim 1, wherein the communication system is supporting aTime Division Multiplexing (TDM).
 5. The method of claim 1, wherein acode included in the portion of the code list is a Walsh code.
 6. Themethod of claim 1, wherein the packet data control channel and thepacket data channel are transmitted simultaneously.
 7. A method ofreceiving packet data in a communication system, comprising: receiving acontrol message on a packet data control channel, the control messagehaving a LWCI field indicating that a code set used in a packet datachannel includes the 0_(th) through the LWCI_(th) codes on a code list;and receiving packet data over the packet data channel using the 0_(th)through the LWCI_(th) codes on the code list.
 8. The method of claim 7,wherein the code allocation information is an index (LWCI) of a lastcode included in the portion of the code list.
 9. The method of claim 8,wherein the portion of the code list includes the 0_(th) through theLWCI_(th) code on the code list.
 10. The method of claim 7, wherein acode included in the portion of the code list is a Walsh code.
 11. Themethod of claim 7, further comprising, detecting a terminal identifieron the packet data control channel; and determining whether the terminalidentifier is matched with an identifier of a mobile station or not. 12.The method of claim 11, wherein the terminal identifier is a MACidentifier.
 13. The method of claim 7, wherein the code list is storedby a mobile station.
 14. The method of claim 7, wherein there is aone-to-one mapping between each code index and each code in the codelist, and wherein code indices in the code list have a sequential rangefrom a first number to a second number.
 15. The method of claim 14,wherein lower code indices are assigned to higher priority codes.